Electronically scanned phased array antenna systems are complex microwave and electronic assemblies. Not only are the electronic drivers associated with such phase shifters complicated, even the interconnection of numerous wires is cumbersome and complicated. The complexity is greatly magnified when relatively large scale two-dimensional arrays of radiators are to be fed (e.g., a 64.times.64 array includes 4,096 separate radiators which must be individually fed with controlled phase RF signals). Of course in a receive mode, incoming RF signals from each of the 4,096 radiators also must be correspondingly selectively phased and combined.
Ferrite or ferrimagnetic phase shifter devices require short pulses of current through magnetizing wires to change the remnant magnetization of one or more ferrite members and thereby change from one "phase state" (i.e., a phase shift of predetermined amount) to another. A related commonly assigned prior issued U.S. Pat. No. 4,445,098--Sharon et al. (the entire content of which is hereby incorporated by reference), explains in more detail how the magnetization of a given ferrite core (or set of cores) typically is first "reset" by magnetically saturating the cores in a first sense. Thereafter, the desired level of remnant magnetization (and hence a corresponding phase state) is achieved by "setting" the core with a controlled current pulse producing a controlled degree of magnetization in the opposite sense.
In short, to reliably and predictably change the phase state of such ferrite phase shifters, a relatively large pulse of current is typically first passed in one direction (or polarity) through a magnetization wire magnetically linked to the core (e.g., by being threaded through the center of an axially extended toroid core) so as to saturate the ferrite in a corresponding sense. After this initial "reset" pulse of relatively large magnitude, then a smaller "set" pulse of current having opposite polarity is passed through a magnetization wire also linked to the core (typically, a separate wire also passing through the toroid center) so as to "set" the phase shifter to a desired remnant state of magnetization (and hence to a desired phase state).
In most practical systems, there is a need to control pairs of ferrite toroids. Each pair may be, for example, two separate phase shifters or a single dual-toroid phase shifter (e.g. see Sharon et al). With this requirement comes the need to supply desired phase shift commands for both toroids and an execution command line. Typically, an interface for this sort of application may require as many as three interface lines for each phase shifter (e.g., data, clock, enable/execute unless one or more of these are bussed in common to all phase shifters).
Accordingly, if such prior interfaces require plural (e.g., three) separate conductors for each phase shifter drive circuit, a 64.times.64 array may require similar multiples of 4,096 lines (plus common ground and power bus lines connected in common to all 4,096 drive circuits). Accordingly, in the prior art example just referenced, as many as three times 4,096 or 12,288 separate conductors (plus the common ground and power bus conductors) may have to be separately routed to and connected to the drive modules. For phased arrays operating in the neighborhood of 10 GHz, the center-to-center spacing between elements of the array is only on the order of 0.6 inch. Furthermore, if the drive circuits are to be physically located near the array aperture (as is desirable), then all of these conductors must be properly routed to a (typically remote) beam steering computer which must rapidly cause all of these lines to have the proper signals placed upon them in a timely manner to effect a desired beam steering function.